LM4900M/NOPB Equivalent & Substitute Parts

Part Overview

The LM4900M/NOPB is a Class AB mono audio amplifier IC manufactured by Texas Instruments, part of the Boomer® series. This 8-SOIC surface mount device delivers 675mW output power at 8Ω load with integrated depop, shutdown, and thermal protection features. The device operates across a 2V to 5.5V supply voltage range and is rated for -40°C to 85°C operating temperature.

The LM4900M/NOPB is classified as obsolete. Substitute components are necessary to maintain design continuity and ensure long-term component availability for new production and legacy system support.

Key Parameters

Parameter	Value
Manufacturer	Texas Instruments
Category	Linear, Amplifiers
Type	Class AB
Output Type	1-Channel (Mono)
Max Output Power @ 8Ω	675mW
Voltage Supply Range	2V ~ 5.5V
Features	Depop, Shutdown, Thermal Protection
Package Type	8-SOIC (0.154", 3.90mm Width)
Mounting Type	Surface Mount
Operating Temperature	-40°C ~ 85°C (TA)
RoHS Status	ROHS3 Compliant
MSL Rating	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution of the LM4900M/NOPB is determined by the following critical parameters:

Electrical Compatibility:

Class AB amplifier topology
1-Channel (Mono) output configuration
8-SOIC package form factor
Operating temperature range: -40°C to 85°C
RoHS3 compliance and MSL Level 1 rating

Functional Compatibility:

Output power rating at 8Ω load (minimum 675mW required for direct substitution)
Supply voltage range overlap (minimum 2V to 5.5V support)
Integrated protection features (thermal protection and shutdown capability)

Mechanical Compatibility:

Surface mount technology
8-SOIC package dimensions (0.154", 3.90mm Width)
Pin-compatible footprint

Substitute parts are grouped by output power capability and feature set. Parts with equal or greater output power and overlapping supply voltage ranges are considered direct substitutes. All substitute parts maintain identical package geometry and thermal specifications.

Parameter Comparison

Part Number	Manufacturer	Product Status	Output Power @ 8Ω	Supply Voltage	Features	Package	Inventory (Pcs)
LM4900M/NOPB	Texas Instruments	Obsolete	675mW	2V ~ 5.5V	Depop, Shutdown, Thermal Protection	8-SOIC	1006
LM4890M/NOPB	Texas Instruments	Active	1W	2.2V ~ 5.5V	Depop, Shutdown, Thermal Protection	8-SOIC	1425
TPA301DR	Texas Instruments	Active	700mW	2.5V ~ 5.5V	Short-Circuit and Thermal Protection, Shutdown	8-SOIC	5145
TPA301D	Texas Instruments	Active	700mW	2.5V ~ 5.5V	Short-Circuit and Thermal Protection, Shutdown	8-SOIC	1125
TPA321D	Texas Instruments	Active	700mW	2.5V ~ 5.5V	Differential Inputs, Short-Circuit and Thermal Protection, Shutdown	8-SOIC	1123
TPA321DR	Texas Instruments	Active	700mW	2.5V ~ 5.5V	Differential Inputs, Short-Circuit and Thermal Protection, Shutdown	8-SOIC	3344
TPA4861DR	Texas Instruments	Active	1.1W	2.7V ~ 5.5V	Short-Circuit and Thermal Protection, Shutdown	8-SOIC	31110
TPA701D	Texas Instruments	Active	700mW	2.5V ~ 5.5V	Short-Circuit and Thermal Protection, Shutdown	8-SOIC	1600
TPA701DR	Texas Instruments	Active	700mW	2.5V ~ 5.5V	Short-Circuit and Thermal Protection, Shutdown	8-SOIC	20400
TPA721DR	Texas Instruments	Active	700mW	2.5V ~ 5.5V	Depop, Short-Circuit and Thermal Protection, Shutdown	8-SOIC	3355
TPA731DR	Texas Instruments	Last Time Buy	700mW	2.5V ~ 5.5V	Differential Inputs, Short-Circuit and Thermal Protection, Shutdown	8-SOIC	1640

Engineering Selection Recommendations

Primary Recommendation: LM4890M/NOPB

The LM4890M/NOPB is the preferred substitute for the obsolete LM4900M/NOPB. Both devices are part of the Texas Instruments Boomer® series and share identical feature sets including depop, shutdown, and thermal protection. The LM4890M/NOPB delivers 1W output power at 8Ω, exceeding the original 675mW specification. Supply voltage range is 2.2V to 5.5V, which overlaps the original 2V to 5.5V specification. The device is in active production status with 1425 units in stock. RoHS3 compliance and MSL Level 1 rating are maintained.

Secondary Recommendations: TPA701DR, TPA701D, TPA721DR

These devices provide 700mW output power at 8Ω, closely matching the original 675mW specification. All three are in active production status with substantial inventory availability. TPA701DR offers the highest stock level (20400 units). Supply voltage range is 2.5V to 5.5V. TPA721DR includes depop functionality, matching the original feature set more closely than TPA701 variants. All maintain RoHS3 compliance and MSL Level 1 rating.

Alternative Recommendations: TPA301DR, TPA301D, TPA321D, TPA321DR

These devices deliver 700mW output power at 8Ω with active production status. TPA321 variants include differential inputs, providing enhanced input flexibility. Supply voltage range is 2.5V to 5.5V. All maintain RoHS3 compliance and MSL Level 1 rating.

Higher Power Alternative: TPA4861DR

The TPA4861DR delivers 1.1W output power at 8Ω with the highest inventory availability (31110 units). Supply voltage range is 2.7V to 5.5V. This device is suitable for applications requiring increased output power headroom. Active production status with RoHS3 compliance and MSL Level 1 rating.

End-of-Life Notice: TPA731DR

The TPA731DR is in Last Time Buy status. While functionally compatible with 700mW output power and differential inputs, this device should not be selected for new designs requiring long-term component availability.

Frequently Asked Questions (FAQ)

Q: Can the LM4890M/NOPB directly replace the LM4900M/NOPB in existing designs?

A: Yes. The LM4890M/NOPB is pin-compatible and functionally equivalent. Both devices use the 8-SOIC package, share identical feature sets (depop, shutdown, thermal protection), and operate across overlapping supply voltage ranges. The LM4890M/NOPB delivers higher output power (1W vs. 675mW), which is compatible with existing designs. No PCB modifications are required.

Q: What is the difference between TPA701D and TPA701DR packaging?

A: Both TPA701D and TPA701DR are electrically and functionally identical. TPA701D is supplied in Tube packaging, while TPA701DR is supplied in Cut Tape (CT) & Digi-Reel® format. Selection depends on assembly process requirements and quantity needs. TPA701DR offers significantly higher inventory availability (20400 vs. 1600 units).

Q: Why do some substitute parts have a minimum supply voltage of 2.5V instead of 2V?

A: The original LM4900M/NOPB operates from 2V minimum supply voltage. Most substitute parts (TPA301, TPA321, TPA701, TPA721, TPA731 series) specify 2.5V minimum. Designs operating below 2.5V must use either the LM4890M/NOPB (2.2V minimum) or verify that the substitute part functions within the specific application's supply voltage range. The LM4890M/NOPB is recommended for applications requiring 2V operation.

Q: Are all substitute parts RoHS3 compliant?

A: Yes. All listed substitute parts maintain RoHS3 compliance and MSL Level 1 (Unlimited) moisture sensitivity rating, matching the original LM4900M/NOPB specifications.

Q: What is the difference between TPA321 and TPA731 devices?

A: Both TPA321 and TPA731 include differential inputs and deliver 700mW output power at 8Ω. The primary difference is product status: TPA321 variants are in active production, while TPA731DR is in Last Time Buy status. For new designs, TPA321D or TPA321DR are preferred. TPA731DR should only be used for legacy system support with limited quantities.

Q: Can I use TPA4861DR as a drop-in replacement?

A: The TPA4861DR is mechanically and electrically compatible (8-SOIC package, Class AB topology, identical operating temperature range). However, it delivers 1.1W output power compared to the original 675mW. This higher power output is suitable for designs requiring increased audio headroom. Verify that the application's output stage and power supply can accommodate the increased power delivery. No PCB modifications are required.

Q: Which substitute part has the best inventory availability?

A: The TPA4861DR has the highest inventory availability with 31110 units in stock, followed by TPA701DR with 20400 units. Both are suitable for high-volume production requirements.

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